Pressure controlled exhaust vent

ABSTRACT

A patient interface includes a mask body, an elbow, a connector and a conduit. Any one or more of the mask body, the elbow, the connector and the conduit includes a bias flow vent. The bias flow vent is configured to deform with the application of pressure but not fully collapse such that an orifice size defined by the bias flow vent can vary with the application of pressure.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention generally relates to bias flow vents for use inCPAP systems. More particularly, the present invention relates to suchvents that are arranged and configured to regulate bias flow such thatit is relatively constant over a wide range of operating pressures.

Description of the Related Art

The treatment of obstructive sleep apnoea (OSA) by continuous positiveairway pressure (CPAP) flow generator systems involves the continuousdelivery of pressurized air to the airways of a human via a conduit andan interface (for example, a mask). Typically, the interface creates atleast a substantial “seal” on or around the nose and/or the mouth. Asthe patient exhales, carbon dioxide gas can progressively collect in thedelivery system. If left unchecked over a period of time, theaccumulation of carbon dioxide can have adverse consequences.

SUMMARY OF THE INVENTION

One solution to the accumulation of carbon dioxide is to provide awashout vent. The washout vent can be provided within the mask system.The washout vent enables a flow of gas to be constantly exhausted to theatmosphere. The constant exhaust flow provides a mechanism tocontinually remove carbon dioxide, which counters the increase in carbondioxide level.

The washout vents, while providing a mechanism for removing carbondioxide, also have a number of trade-offs. State of art practicecurrently uses a hole/hole array of fixed dimensions. The fixeddimensions have the effect of enabling a bias flow of gas that increasesas the CPAP pressure level increases. This increasing flow hasimplications for a number of parameters that affect the user.

The bias flow exiting through the washout vents typically createsdisturbances for the patient and/or the patient's bed partner. Thedisturbances typically manifest in two forms: noise and draft. Changesin the bias flow rate, which are caused by changes in the CPAP pressurelevel, directly affect the magnitude of these disturbances. Thus, if apressure oscillation exists within the system, then it is possible toproduce an oscillating disturbance.

The flow and humidity source (for example, blower and humidifier) alsocan be impacted. Increasing the bias flow results in an increase in thephysical dimension and power consumption to cater to the peak flowdemand (that is, the sum of patient requirements and the maximum biasflow at peak pressure).

The creation of practical and not so practical solutions to this hasbeen the subject of considerable development efforts. Yet, there is roomfor continued improvement in resolving the problems associated withreducing or eliminating the accumulation of carbon dioxide within a CPAPsystem.

Certain aspects relate to a patient interface. The patient interface hasa body portion sized and shaped to surround a nose and/or a mouth of auser and adapted to create at least a substantial seal with a face ofthe user. The patient interface also has a coupling that permits thepatient interface to be coupled to a gas delivery system. The patientinterface further has a vent that allows passage of gas from an interiorof the body portion of a mask to an exterior of the body portion of themask wherein a portion of the vent comprises means to regulate a flow ofgas based on the applied pressure.

In some configurations, the means to regulate flow comprises an orificeconstructed with varying wall section thickness.

In some configurations, the wall section thickness varies in the rangeof 50 to 400 microns.

In some configurations, the means to regulate flow operates in apressure range of 1 cmH2O to 40 cmH2O.

In some configurations, the means to regulate flow occurs without adeformable orifice entirely collapsing.

In some configurations, the means to regulate flow comprises one or morelobes formed by one or more surfaces and the means to regulate occurswithout the one or more surfaces coming into contact with itself orthemselves.

Certain aspects relate to a valve for use with system for deliveringCPAP therapy. The valve comprises a base and a membrane. The membranehas a first end defining an inlet opening. The base has a second enddefining an outlet opening. The first end of the membrane has at leastone concave portion and at least one convex portion and the first end ofthe membrane is configured to collapse inwardly to vary a flow path sizein response to changes in pressure acting on the membrane.

In some configurations, the at least one concave portion and the atleast one convex portion are defined by an inflection on an outersurface of the membrane.

In some configurations, the at least one concave portion and the atleast one convex portion are defined by an inflection on an innersurface of the membrane.

In some configurations, the at least one concave portion and the atleast one convex portion are defined by a change in membrane thickness.

In some configurations, the at least one concave portion and the atleast one convex portion are defined by a change in membrane thicknessand an inflection on at least one of an inner surface and an outersurface of the membrane.

In some configurations, the at least one concave portion comprises alobe and the at least one convex portion comprises a bridging portion.

In some configurations, the valve comprises only two lobes and only twobridging portions.

In some configurations, the valve comprises only three lobes and onlythree bridging portions.

In some configurations, the valve comprises only four lobes and onlyfour bridging portions.

In some configurations, the valve comprises a triangular base.

In some configurations, the valve comprises a circular base.

In some configurations, the base can have a first geometric shape andthe inlet opening defined by the membrane can have a second geometricshape. In some such configurations, the first geometric shape is thesame as the second geometric shape. In some such configuration, thefirst geometric shape is triangular and the second geometric shape istriangular. In some such configurations, the first geometric shape isdifferent from the second geometric shape. In some such configurations,the first geometric shape is circular and the second geometric shape istriangular.

In some configurations, the transition between the base and the inletopening defined by the membrane is non-linear. In some suchconfigurations, the transition is arcuate. In some configurations, themembrane can have a first portion that transitions in a non-linearmanner away from the base but symmetrically to the base and a secondportion that transitions from the first portion in a non-linear mannerto the inlet but non-symmetrically to the base.

In some configurations, the valve further comprises a splint thatextends into a mouth defined by the first end of the membrane.

In some configurations, the splint extends from the first end of themembrane to the second end of the base.

In some configurations, the valve further comprises a bias materialdisposed at the second end of the base.

In some configurations, the bias material comprises a plurality of biasflow holes.

In some configurations, the bias material comprises a diffuser.

In some configurations, a valve array comprises at least two of thevalves.

In some configurations, the at least two valves comprise two rows ofvalves.

In some configurations, the two rows of valves are nested together.

In some configurations, the two rows have valves disposed side by side.

In some configurations, the at least two valves comprise a predeterminedpattern of valves.

In some configurations, the valve array is combined with a mask, thevalve array being mounted to the mask.

In some configurations, the valve array is disposed on a seal housing ofthe mask.

In some configurations, the valve array is disposed on a seal of themask.

In some configurations, the valve array is disposed on a frame of themask.

In some configurations, the mask comprises an exhaust conduit and thevalve array is disposed in the exhaust conduit.

In some configurations, the valve array is combined with an elbow, thevalve array being mounted to the elbow.

In some configurations, the valve array is mounted to a cover that isassociated with the elbow.

In some configurations, the cover is removable from the elbow.

In some configurations, the valve array is combined with a swivel, thevalve array being mounted to the swivel.

The following describes some practical options to improve currentdesigns.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the presentinvention will now be described with reference to the drawings ofseveral preferred embodiments, which embodiments are intended toillustrate and not to limit the invention, and in which figures:

FIG. 1 is a graphical representation of Bias Flow v. Applied Pressure ina system using prior bias flow vent configurations.

FIG. 2 is a graphical representation of Bias Flow v. Applied Pressure ina system using bias flow vent configurations arranged and configured inaccordance with certain features, aspects and advantages of the presentinvention.

FIG. 3 is a perspective view of a bias flow valve arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention.

FIG. 4 is a top view of the bias flow valve of FIG. 3.

FIG. 5 is a schematic sectioned view of the bias flow valve of FIG. 3.

FIG. 6 is an enlarged view of a portion of the bias flow valve of FIG.3.

FIG. 7 is a perspective view of a bias flow valve arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention.

FIG. 8 is a top view of the bias flow valve of FIG. 7.

FIG. 9 is a top view of the bias flow valve of FIG. 7 when subjected tohigher pressures.

FIGS. 10-13 are sections of different bias flow valve configurationshaving differing numbers of lobes and/or differing lobe constructions.

FIGS. 14 and 15 are bias flow valves arranged and configured inaccordance with certain features, aspects and advantages of the presentinvention.

FIG. 16 is a graphical depiction of the effect of valve size and valvenumber on pressure and loudness.

FIGS. 17-24 are various configurations featuring a plurality of biasflow valves in valve arrays.

FIG. 25 is a bias flow valve in combination with a bias material.

FIGS. 26 and 27 illustrated a bias flow valve in combination with anelbow.

FIGS. 28-30 illustrate a mask in combination with a valve array.

FIG. 31 is a graphical depiction of various combinations of valves, biasflow holes and diffusers and the impact of each combination on pressureand flow.

FIG. 32-35 show the combinations used to generate the graphicaldepiction of FIG. 31.

FIG. 36 is a graphical depiction of the effect of the combinations ofFIG. 32-35 on pressure and loudness.

FIGS. 37-41 illustrate combinations of valves and other components in aCPAP system.

FIG. 42 is a graphical depiction of the impact of parallel bias valveson flow rate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As described above, certain features, aspects and advantages of thepresent invention relate to providing a bias flow that has significantless variance in flow rate over a normal operating pressure range forCPAP systems.

FIG. 1 shows the performance of a conventional bias hole array over avariety of CPAP pressure levels. It can be seen that the bias flowincreases by approximately 100% (that is, from about 18 L/min to about42 L/min) as the pressure is increased from 4 cmH2O to 20 cmH2O. FIG. 2shows the performance of one embodiment of a constant bias flow controlsystem arranged and configured in accordance with certain features,aspects and advantages of the present invention. The illustratedperformance is under varying CPAP levels. It can be seen that the biasflow increases by approximately 40% (that is, from about 13 L/min toabout 20 L/min) as the pressure is increased from 4 cmH2O to 20 cmH2O.

As shown by comparing FIG. 1 and FIG. 2, the constant bias flow controlsystems that are arranged and configured in accordance with certainfeatures, aspects and advantages of the present invention enableenhanced control over the sound intensity and/or the drafts created asthe bias flow exits the CPAP system. Furthermore, the illustratedconstant bias flow control systems reduce the flow overhead required inthe flow source/CPAP source to accommodate the phenomenon shown inFIG. 1. Because the flow source/CPAP must make up for the everincreasing flow that simply exits through the bias flow vents, the flowsource/CPAP size and energy requirement of the flow source/CPAP sourcemust be increased relative to an ideally sized unit.

Valve Geometry

FIG. 3 illustrates a bias flow control valve 10 that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention. The bias flow control valve 10 advantageouslyalters the flow opening over a range of pressures. In other words, asthe pressure in the system increases, an outlet for gases defined by thebias flow control valve 10 constricts, thereby acting to reduce the biasflow as compared to prior bias flow constructions.

In some configurations, the valve 10 may be formed of silicone rubber(or other suitable thermoplastic elastomers). Silicone containshydrophobic characteristics that are beneficial for reducing oreliminating condensation build up in or on the valve 10 during use. Anyother suitable material or combination of materials can be used. In someconfigurations, a less flexible portion of the valve 10 may be formed ofa first material and a more flexible portion of the valve 10 may beformed of a second, less resilient, material when compared to the firstmaterial.

The illustrated bias flow control valve 10 comprises a base 12. The base12 can include a flange or a rim. In the arrangement of FIG. 3, forexample, the base 12 is ring-like and can define an outer ring. In otherwords, in the arrangement of FIG. 3, the base is generally circular inconfiguration. As shown in FIG. 7, the base 12 does not have to becircular but can have any other desired shape. In some configurations,the base 12 can be a smooth, non-circular or non-cylindrical shape, suchas the triangular shape of FIG. 7. The shape of the base can vary fromconfiguration to configuration. By varying the shape of the base,different geometries of surrounding structures can be accommodated. Insome configurations, multiple valves are used and, by having the base 12have a triangular shape, for example but without limitation, anincreased number of valves 10 can be mounted over a predeterminedsurface area. The shape of the base 12 can vary between two or morevalves in a single multi-valve configuration or the shape of the base 12can be consistent between all valves in a single multi-valveconfiguration.

The base 12 facilitates coupling or connection to the component to whichthe bias flow control valve 10 is mounted. Any suitable configurationcan be used keeping in mind a desire to join the valve 10 to thecomponent in or to which it is mounted. In some configurations, thevalve 10 is not removable from the component in or to which it ismounted without significant destruction to the valve 10 and/or thecomponent. In some such configurations, the base 12 forms an integralportion with a surrounding structure.

A membrane 14 can be connected to the base 12 in any suitable manner. Insome configurations, the membrane 14 can be integrally formed with thebase 12. The membrane 14 is relatively more flexible than the base 12.With reference to FIG. 5, in the illustrated configuration, an outlet 16can be defined by the base 12 and an inlet 18 can be defined by themembrane 14. The inlet 18 and the outlet 16 are axially offset from eachother in the direction of flow (that is, along the central axis of thevalve 10). In some configurations, the inlet 18 and the outlet 16 can beaxially offset by different distances at different operating pressures.In some configurations, the inlet 18 moves toward the outlet 16 aspressure within the system increases.

In some configurations, such as shown in FIG. 3, the base 12 and theinlet 18 defined by the membrane 14 can have different geometries (forexample, a circular base 12 with a triangular inlet 18). In someconfigurations, such as shown in FIG. 7, the base 12 and the inlet 18can have similar geometries (for example, a triangular base 12 and atriangular inlet 18). In some configurations, the transition between thebase 12 and the inlet 18 is non-linear (that is, even when transitioningfrom a triangular base to a triangular opening, the wall has an arc incross-section instead of a linear progression). Such a non-linearconfiguration, for example, can be seen in FIG. 3, FIG. 5, and FIG. 7.In some configurations, the membrane 14 can have a first portion thattransitions in a non-linear manner away from the base 12 butsymmetrically to the base and a second portion that transitions from thefirst portion in a non-linear manner to the inlet 18 butnon-symmetrically to the base.

In terms of flow path size, the inlet 18 is a first size in a firstcondition and the inlet 18 is smaller in a second condition. That is,under a first operating pressure in the system, the inlet 18 can have afirst size and, under a second operating pressure in the system that ishigher than the first operating pressure, the inlet 18 can have a secondsize that is smaller than the first size. In other words, the outlet 16can have a first inner perimeter length and the inlet 18 can be definedby a rim 20 formed on the membrane 14 with the inlet 18 having a secondinner perimeter length. The second inner perimeter length can be lessthan the first inner perimeter length. In some configurations, the inlethas an opening with three lobes 22 and an opening area of 18.5 mm2. Insuch configurations, the valve 10 can be used alone as a single valveand transmit an initial flow of 15 L/min at a CPAP pressure of 5 cmH2O.

As shown in FIG. 5, the inlet 18 is disposed into the direction fromwhich the flow originates. Thus, the membrane 14 is positioned on thehigher pressure side of the base 12 in the illustrated configuration. Asshown in FIG. 5, at least a portion of the membrane 14 can deflect withthe application of pressure (for example, the dotted lines show thedeflection of the valve 10). The deflection of the membrane 14 serves toconstrict at least a portion of the flow passage through the valve. Inthe illustrated configuration, the deflection of the membrane 14 servesto constrict the inlet 18 to the valve 10. In some configurations, themembrane 14 deflects in two directions (that is, one or more of thewalls surrounding the opening of the inlet 18 deflect inwardly todecrease the flow path through the opening and the inlet 18 movesaxially toward the outlet).

As shown in FIG. 4, the rim 20 can define two or more lobes 22. Eachlobe 22 can be connected to an adjacent lobe 22 with a bridging portion24. The lobes present themselves as concave regions (that is, concavewith respect to the center axis of the passageway defined through thevalve 10). The bridging portions 24 can present themselves as convexregions (that is, convex with respect to the center axis of thepassageway defined through the valve 10).

Any number of lobes can be used. More than one lobe has been found to beeasier to design and manufacture that a single lobe in order to get thedesired repeatability and controllable closing of the opening. FIG. 10shows a three lobe configuration. Each of FIGS. 11 and 12 shows a twolobe configuration. FIG. 13 shows a four lobe configuration. From astability standpoint and an ease of design and manufacture standpoint,the three lobe configuration has been a favored configuration.

In some configurations, the lobes 22 can be symmetrically disposed aboutthe central axis CA. In some configurations, the apex of each lobe 22can be equidistant from the central axis CA. In other words, the apex ofeach lobe 22 is spaced from the central axis CA the same distance at theapex of each of the other lobes 22. In some configurations, the apex ofeach lobe 22 can be equidistant from the central axis CA with respect tothe apex of any diametrically opposed lobe 22. In some configurations,the apex of each lobe 22 is equidistant from the central axis CA and anincluded angle between each of the lobes is equal for all of the lobes22. In other words, the lobes 22 are symmetrically spaced about thecentral axis CA. In some configurations, the lobes 22 are not allsymmetrically spaced about the central axis CA but are spaced in one ormore symmetrical patterns. Other configurations also are possible.

In some configurations, an inner member 26 can be positioned within thevalve 10. The inner member 26 can be used with any valve configurationdescribed herein. The inner member 26 can be positioned in the region ofthe inlet 18. The inner member 26 can be a rigid tube in someconfigurations. The inner member 26 provides a minimum flow passage suchthat, if the membrane 14 were to collapse fully around the inner member26, the inner member would maintain a flow path. As such, in someconfigurations, the inner member 26 is a single tube with an inner lumen28. In some configurations, the inner member 26 is a plurality of poststhat maintain a flow path through the valve 10 by reducing oreliminating the likelihood of a total closure of the valve 10. Ineffect, the inner member 26 can be any component that acts as a splintto hold open at least a portion of the valve 10 when the valve is in anotherwise closed position. The opening that is preserved can be relatedto a desired flow at the maximum operating pressure of the CPAP machineor other flow generator.

With reference to FIGS. 14 and 15, the illustrated inner member 26 ismounted to a support structure 30. The support structure 30 can supportthe inner member 26 in position without significantly impacting flowthrough the valve 10. The illustrated support structure 30 comprises oneor more cross members 32. In the illustrated configuration, the innermember 26 can extend from the inlet 18 to the outlet 16 and can besupported at any desired location along the length of the inner member26. In some configurations, the support structure 30 can be positionedwithin the base 12. In some configurations, the support structure 30 canbe positioned adjacent to the outlet 16.

One or more of the adjacent regions of the valve can close off againstan outer surface of the inner member 26 as the flow generator increasesthe pressure. Through the use of the inner member 26, a flow paththrough the valve 10 can be maintained. Such configurations can reduceor eliminate the likelihood of the valve 10 inverting, closing offcompletely at high pressures or overly limiting flow at higherpressures, which may occur, for example, when a user coughs. In someconfigurations, the inner member 26 can be formed of the same materialas the rest of the valve 10. In some configurations, the inner member 26can be formed of different materials relative to the rest of the valve10. In some configurations, the inner member 26 can have a wallthickness of the same material as used for the membrane but with a wallthickness sufficient to maintain an open flow path through the membrane.In some configurations, the inner member 26 can be formed of the samematerial used to form the base 12.

In configurations now featuring the inner member 26, the shape and/orthe varying thicknesses and/or stiffnesses surrounding the openingdefined by the inlet 18 can help reduce or eliminate the likelihood ofthe valve 10 entirely collapsing and can help reduce or eliminate thelikelihood of the valve 10 sticking shut in use. In constructionswithout the inner member 26 as well as those with the inner member 26,the wall thickness can change around a given cross section (see FIG. 6);the wall thickness also can change along the principal axis of the valve10 (see FIG. 5). The illustrated changes in wall thickness help toprovide a smooth constricting mechanism across the operating pressurerange for treating sleep apnoea or other respiratory care patents.

With reference again to FIG. 6, in some configurations, the wallthickness of the membrane can be varied at and/or near the rim 20. Insome configurations, the wall thickness of the membrane can be varied atthe rim 20 and axially along at least a portion of the membrane in thedirection of the outlet outer rim 20. Such a wall thickness variance isshown in the cross section of FIG. 5, where the wall tapers from thebase 12 to the inlet 18. As also illustrated in FIG. 6 and FIG. 8, forexample, the wall defined by the membrane 14 can be relatively thickerin the lobes 22 and relatively thinner in the bridging portions 24. Sucha configuration increases the likelihood of controlled collapsing of theinlet 18 when pressure is applied to the outer wall of the membrane 14.

If the thickness in the bridging portions 24 is too thick, then thevalve 10 may be less deformable and may not close enough and, if thethickness in the bridging portions 24 is too thin, then the valve 10 maybe too deformable and may close too much. In some silicone rubberconfigurations, the wall sections of the constructed valve 10 can be inthe range of 100 to 400 microns for the relatively thicker portions and50 to 300 microns for the relatively thinner portions. In theconfiguration of FIG. 6, the apexes of the lobes 22 can have a thicknessof 300 microns while the middle region of the bridging portions 24 canhave a thickness of 200 microns. A transition between the thicker lobes22 and the thinner portion of the bridging portion 24 (that is, atransition between the concave lobes 22 and the convex bridging portions24) can assist in resisting collapse of the valve 10. If the outerradius of the lobes 22 is reduced from 1.3 mm to 1.2 mm or 1.25 mm, thevalve 10 of FIG. 6 collapses too easily. The centres of the inner andouter radii of the concave portions 22 in the valve 10 of FIG. 6 areoffset by 0.1 mm along radial axes that extend from the centre of theopening.

As illustrated in, for example, FIG. 12, the wall of the membrane 14that defines the lobes 22 and the bridging portion 24 can have a uniformthickness about the entire periphery of the rim 20. In some suchconfigurations, the geometry can be tuned to obtain the desiredcollapsing characteristics. In some such configurations, the materialcan be varied to provide a stiffer portion in the lobes 22 and a moreflexible portion in the bridging portions 24. Any other suitablecombination of these or any other suitable configuration can be used toobtain a valve that at least partially collapses upon itself asdescribed herein.

The lobes 22 provide stiffness to reduce or eliminate the likelihood ofthe valve inverting under high pressures. In general, however, thestiffness of the membrane 14 is defined by the thickness in the lobes22, the profile of the wall, the height of the valve 10 and theproperties of the material used to make the valve. As shown in FIGS. 8and 9, the valve 10 deforms in a way that narrows the flow passage and,thereby, reduces the level of flow that can be passed through the valve10. In FIG. 8, the valve is shown with no operating pressure (that is, 0cmH2O) while, in FIG. 9, for example, the valve is shown under apressure of greater than 1 cmH2O. As shown in FIG. 9, under theapplication of pressure to the membrane 14, the thinned wall sectiondeforms, which results in changes to the flow passage defined throughthe lobe 22 cross sectional area changing, which in turn changes theflow rate that is possible through the flow passage defined through thelobe 22 based on the pressure differential that exists across the valve10. By varying the relative portions of the thick to thin (or more stiffto more flexible), the performance of the valve 10 can be tuned forspecific operating pressure ranges. In some configurations, one or moredeformable orifice does not entirely collapse within the range of normaloperating pressures. In some configurations, each lobe can include oneor more surface and the one or more surfaces do not come into contactwith itself or themselves within the range of normal operatingpressures. Thus, one or more of the lobes, the bridging portions and thevaried thicknesses, at least in part, can define means to regulate aflow of gas based on the applied pressure.

Valve Arrays

As shown in FIG. 42, using multiple small valves 10 can approximate theflow characteristics of a single larger valve, but using multiple smallvalves 10 can reduce the noise relative to using a single valve 10having the same throughput. This is because the multiple small flowrestrictions will result in small pressure drops across each valveresulting in less turbulence and less noise generation. This isdemonstrated in the graphical depiction of FIG. 16. As illustrated,within increasing pressures, a single large valve arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention is demonstratively louder than two smallvalves. Moreover, the data shows that the increase in loudness for twosmaller valves increases significantly less over the illustrated largervalve.

With reference now to FIGS. 17-24, any configuration of the valve 10described above can be used in a valve array 40. The valves 10 used inan array can be miniaturized relative to a single valve 10. To be clear,the valves 10 that make up the valve array 40 can be uniform inconfiguration or can be assorted in configuration. In some valve arrays40, the valves 10 are configured to have the same operatingcharacteristics uniformly across the field of the array 40. In somevalve arrays 40, one or more of the valves 10 may be configured tobehave differently relative to others at the same operating pressures.In some configurations, twenty valves will be used to provide anapproximate cross sectional area of about 22 mm2. Other numbers ofvalves can be used and other cross sectional areas can be used.

With reference to FIG. 17, a multivalve component 42 is illustrated. Themultivalve component 42 comprises an array 40 of valves 10. The valves10 are configured as described above. A common base 12 connects thevalves 10 in the illustrated configuration. In some configurations, thecommon base 12 can be formed in multiple pieces that are connected orinterconnected. In some configurations, the base 12 of each valve can bereceived within a receptacle or opening of a plate that serves as thecommon base. Any other configurations can be used.

With continued reference to FIG. 17, the valves 10 in the illustratedconfiguration are spaced in a symmetrical pattern. The rotationalorientation of the valves 10 is such that two of the valves 10 arerotated 180 degrees relative to two of the other valves 10. In otherwords, the apex of the lobes 22 of two of the valves 10 points towardthe apex of the lobes 22 of the other two of the valves 10. In someconfigurations, the four valves 10 can be orientated such that one ofthe lobes 22 of each of the valves 10 points toward a center of themultivalve component. Other orientations of the valves 10 also arepossible.

With reference now to FIG. 18, the illustrated array 40 of valves 10 isshown on a multivalve insert 44. The multivalve insert 44 can compriseany desired number of valves 10 to provide a desired level of flow. Inthe illustrated configuration, the multivalve insert 44 comprises twentyvalves 10. The valves are arranged in four rows and five columns in theillustrated configuration. In the illustrated configuration, the valves10 also are oriented in a single direction. Other configurations arepossible.

The multivalve insert 44 can be formed in any suitable manner of anysuitable material. For example, in some configurations, the multivalveinsert 44 can be formed of a single material. In some suchconfigurations, the entire multivalve insert 44 can be formed of amaterial such as silicone or any suitable thermoplastic elastomer. Theconfiguration of FIG. 18 is completely formed of a single such material.

With reference to FIG. 19, the illustrated multivalve insert 44 is thesame as the multivalve insert 44 illustrated in FIG. 18 except themultivalve insert 44 in FIG. 19 comprises a substrate material 46. Thesubstrate material 46 can be the same material used to form the valves10 or can be a different material. In some configurations, the substratematerial 46 provides a rigid base for the valves 10 of the multivalveinsert 44.

FIG. 20 schematically illustrates another multivalve component 42. Themultivalve component 42 illustrated in FIG. 20 comprises a plurality ofrows of valves 10. The valves 10 have one row with a first orientationand a second row with an opposite orientation; the two adjacent rows ofvalves 10 are nested. By nesting the valves 10, a greater valve densitycan be obtained.

With reference now to FIG. 21, a further valve array 40 on a multivalvecomponent 42 is illustrated. The valves 10 in the illustratedconfiguration are arranged in a pattern of rows having unequal numbersof valves 10. The illustrated configuration features three rows ofvalves 10 with the center row having more valves 10 than the outer rows.In particular, the center row has one additional valve 10 at each end ofthe row.

FIG. 22 illustrates a valve array 40 on a multivalve component 42. Thevalves 10 in the valve array 40 have a non-linear layout. The valves 10may be arranged in a manner that can be predetermined by the designer.

FIG. 23 illustrates another valve array 40 on a multivalve component 42.In the illustrated configuration, the valves 10 are arranged indifferent rows. The center two rows have nine valves 10 arrangedside-by-side. Each of the center rows is flanked by an intermediate rowthat is in turn flanked by an outside row. Each intermediate rowincludes seven valves 10. Each outside row includes three valves 10. Thevalves 10 in the outside rows can be aligned with the valves 10 in thecenter rows while the valves 10 in the intermediate rows can be offsetfrom the valves in the center rows and the outside rows.

FIG. 24 shows a further valve array 40 on a multivalve component 42. Inthe illustrated configuration, the valves 10 form two staggered lines.The valves 10 can be used to like the periphery of a component of a masksystem or the like.

Any of the valve configurations described herein can be incorporatedinto a breathing mask or related component. For example, the valvearrays 40 can be incorporated into a nasal mask, a pillows mask, a fullface mask, a conduit, an elbow, or the like. In addition, it is possibleto integrate traditional bias flow holes into the valve arrays such thatthe bias flow holes and the valves 10 are used together in a singlearray or component. In some configurations, a line of valves can beflanked by a row of bias flow holes. In some configurations, a line cancontain valves and bias flow holes. Any other suitable configuration canbe used.

System Components Featuring Valves

In the following discussion, the term “valve” will include “valve array”unless otherwise apparent. The bias flow control valve 10 can bepositioned in any suitable location keeping in mind a desire to allowevacuation of carbon dioxide from within the system where the carbondioxide is introduced through exhalation. The valve 10 preferably is notthe only flow path between the patient and the flow generator (forexample, CPAP). In other words, the air flow must have a path to travelfrom the flow generator to the patient without passing through the valve10. Without the alternative flow path, the pressure drop through thevalve 10 would mean that the patient was not receiving the prescribedpressure. The valve 10 can be placed anywhere in the system that a biasvent arrangement could be placed. In some configurations, the valve 10can be placed in front of or behind or as a replacement for the biasvent arrangement. Further, the valve 10 can be placed so that the axisof the valve 10 is perpendicular to the surface or can be on an angle tothe surface in order to better provide directional control to the flowemanating from the valve 10.

In some configurations, the valve 10 can be positioned between thepatient and the bias flow holes. In some configurations, however, such apositioning may lead to increased noise and/or decreased or impairedvalve performance. For example, a system with a larger pressure dropacross the bias flow holes (for example, a smaller cross sectional areaof the holes) than across the valve 10 could decrease the performance ofthe valve 10. To address such an issue, the valve 10 could be providedwith less stiffness. In some configurations, a system with a pressuredrop that is higher across the valve than the bias flow holes couldresult in increased noise generation as the air jets onto the surfaceand through the bias flow holes. This can be reduced by having a largerchamber between the bias flow holes and the valve and by minimizing thepressure drops between the two parts. In some configuration, this can beaddressed by providing a hollow frame or shroud through which ventingcan occur.

With reference to FIG. 25, the valve 10 can be placed in line with oneor more bias flow holes 50. By positioning the valve 10 in line with thebias flow holes 50, the holes 50 can quiet the sound of a larger valve10. This is particularly advantageous because a larger valve 10 iseasier to manufacture than the smaller valves used in the valve arrays40 discussed above. It is possible to place a valve array 40 in linewith the bias flow holes 50 as well. It also is possible to use adiffuser in place of or further in line with the bias flow holes 50.

In some configurations, the bias flow control valve 10 can be positionedon an interface. In some configurations, the bias flow control valve 10can be positioned on a mask. In some configurations, the bias flowcontrol valve 10 can be positioned on a connector that is positionedbetween a conduit and a mask. In some configurations, the bias flowcontrol valve 10 can be positioned on a conduit that connects to themask. The bias flow control valve 10 can be used with any suitable maskconfiguration (not shown). The mask can include a body portion sized andshaped to surround the nose and/or mouth of the user. The mask can beadapted to create at least a substantial seal with the user's face. Thebody portion of the mask can have an interior and an exterior. The maskcan include a coupling that permits the patient interface to be coupledto the gas delivery system. The bias flow control valve 10 allows thepassage of gas from the interior of the body portion of the mask to theexterior of the body portion of a mask.

With reference now to FIGS. 26 and 27, the valve 10 can be mounted to aconnector structure, such as an elbow 60. As illustrated, the elbow 60can include an opening 62. The opening can receive at least a portion ofthe valve 10. In some configurations, the valve 10 is mounted to a cover64. The cover 64 can be permanently secured or removably connected tothe elbow 60. In some configurations, the valve 10 and the cover 64 canbe connected by overmoulding or the like. In some configurations, a biasmaterial 66 can be mounted to the cover 64 or otherwise be positionedsuch that flow through the valve 10 also flows through the bias material66. The bias material can be a group of bias flow holes or a diffuserscrim material or the like. While the illustrated configuration is on anelbow, a similar configuration can be used elsewhere on the mask, on theconduit or on a connector, for example.

With reference now to FIGS. 28-30, a mask 70 is illustrated thatintegrates a valve array 40 that is arranged and configured as describedabove. The mask 70 generally comprises a seal housing 72 and acushioning seal 74.

In the illustrated configuration, the seal housing 72 comprises amultivalve insert 44 such as that described above, for example butwithout limitation. The multivalve insert 44 can be removable in someconfigurations (for example, clipped into position). The multivalveinsert 44 can be moulded into the mask 70 (for example, moulded into theseal housing 72). As described above, the valves 10 can be supported bya flexible base or can be supported by a more rigid substrate material.In some configurations, instead of the multivalve insert 44 featuringmultiple valves 10, a single valve 10 can be used. In someconfigurations, instead of one valve array 40, more than one valve array40 can be used (that is, more than one group of valves).

In the event that no biasing material is used such that the valve 10 orvalves 10 vent directly to atmosphere, then multiple valves 10 arepreferred. In the illustrated configuration, however, a plenum chamber76 is defined between the multivalve insert 44 and a biasing material66. The plenum chamber 76 can be larger than illustrated in someconfiguration. In addition, it is possible to include a hollow framethat the valve or valve array vents into.

With reference to FIG. 31, a graphical depiction is provided that showsvarious flows at various pressures for embodiments of the mask 70 thatinclude: (1) a large valve with bias flow holes; (2) a large valve; (3)bias flow holes; and (4) a large valve with a diffuser material. Theseconfigurations are illustrated in FIGS. 32-35. As illustrated in thegraphical depiction, having the bias flow holes changes the performanceof the mask 70. The maximum flow rate is approximately the same as whenthere are no holes in line with the valve, but the flow does not dropaway until a higher pressure is applied. Having the bias flow holes inline with the valve would therefore be improved by changing the valveconfiguration, but does not necessarily result in a reduction ofperformance of the mask 70.

With reference to FIG. 36, a graphical depiction is provided that showsvarious loudness data points at various pressures for the sameembodiments of the mask 70 as discussed directly above. As can be seen,in order to reduce the noise of the valve 10, it is best to incorporatea diffuser material after the valve.

FIG. 37 illustrates another configuration in which the multivalve insert44 is positioned on the elbow 60. The configuration can be similar tothat shown in FIGS. 28-30 and can incorporate the same elements: thevalves 10, the valve array 40, the multivalve insert 44, the biasmaterial 66, and the plenum chamber 76. In the illustratedconfiguration, the elbow 60 comprises the multivalve insert 44, such asthat described above, for example but without limitation. The multivalveinsert 44 can be removable in some configurations (for example, clippedinto position). The multivalve insert 44 can be moulded into the elbow60. As described above, the valves 10 can be supported by a flexiblebase or can be supported by a more rigid substrate material. In someconfigurations, instead of the multivalve insert 44 featuring multiplevalves 10, a single valve 10 can be used. In some configurations,instead of one valve array 40, more than one valve array 40 can be used(that is, more than one group of valves).

In the event that no biasing material is used, such that the valve 10 orvalves 10 vent directly to atmosphere, then multiple valves 10 arepreferred. In the illustrated configuration, however, a plenum chamber(not shown but similar to that of the mask embodiment) is definedbetween the multivalve insert 44 and a biasing material 66. It ispossible to include a hollow frame that the valve or valve array ventsinto.

FIG. 38 illustrates a configuration in which a secondary exhaust tube 80can be provided to the mask 70. The secondary exhaust tube 80 caninclude a valve 10 at the end of the exhaust tube 80. The valve 10 canrestrict exhaust flow. The secondary exhaust tube 80 with the valve 10provides a benefit of venting remotely from the user. In such remotelocations, the noise of the valve is perceived to be less of a concern,for example. In some configurations, the secondary exhaust tube 80 cantravel along at least a portion of a supply tube 82. In someconfigurations, the exhaust tube 80 can travel alongside of the intaketube 82. In some configuration, the exhaust tube 80 can be positionedcoaxially within the intake tube 82. In some configurations, the exhausttube 80 can surround at least a portion of the intake tube 82. Otherconfigurations are possible.

With reference to FIG. 39, a further configuration for a mask 90 isshown. The mask 90 includes a frame 92 to which a mask seal 94 can besecured. The mask frame 92 can include a ring 96. The ring 96 can atleast partially encircle a socket 98 that receives an elbow, connector,conduit or the like. The ring can be provided with one or more valves10. In some configurations, several small valves 10 can be disposedaround the ring 96. By separating the valves, interference between theair flowing out of adjacent valves can be reduced, which thereby reducesturbulence and noise. In some configurations, the valves can beintegrally formed with the ring 96 or other mounting structure. In someconfigurations, the ring 96 or other mounting structure can beintegrally formed (for example, overmoulded) with the frame 92. In someconfigurations, the ring or other mounting structure can be removablyattached to the frame 92. In some configurations, the ring or othermounting structure can be separately formed from the frame 92 and can besecured to the frame in any suitable manner.

With reference to FIG. 40, a configuration of the mask 90 is shown inwhich the valves 10 are positioned on the mask seal 94. Because the maskseal 94 generally is formed of silicone or another similar material, thevalves 10 can be integrated into the mask seal 94 and thereby reducemanufacturing steps. In some embodiments, the valves 10 can be groupedtogether on particular regions of the mask seal 94. In someconfigurations, there may be a group of valves 10 on each lateral sideof the mask seal 94. In some configurations, there may be a group ofvalves 10 on the top of the mask seal 94. In some configurations, theremay be a group of valves 10 on the bottom of the mask seal 94. Anycombination of these groups also can be used. In some configurations,each of the valves 10 in any single group may be aligned in a singledirection such that the flow from the valves 10 is in the samedirection. In addition, aligning groups of valves advantageouslysimplifies manufacturing by providing a single draw plane for simplifiedmoulding.

With reference now to FIG. 41, one or more valves 10 can be incorporatedinto a swivel connector 100. The swivel connector 100 can connect aconduit to a mask. The swivel connector 100 can include an outer flange102. The outer flange 102 receives an inner member 104. A plenum chamber106 can be defined between the outer flange 102 and the inner member104. The valves 10 can be disposed around the inner member 104, forexample, such that the valves direct flow into the plenum chamber 106.Other suitable configurations also can be used.

Although the present invention has been described in terms of certainembodiments, other embodiments apparent to those of ordinary skill inthe art also are within the scope of this invention. Thus, variouschanges and modifications may be made without departing from the spiritand scope of the invention. For instance, various components may berepositioned as desired. Moreover, not all of the features, aspects andadvantages are necessarily required to practice the present invention.Accordingly, the scope of the present invention is intended to bedefined only by the claims that follow.

What is claimed is:
 1. A valve for use with system for delivering CPAPtherapy, the valve comprising a base and a membrane, the membrane havinga first end defining an inlet opening disposed into a direction fromwhich flow originates, the base having a second end defining an outletopening, the first end of the membrane having at least one concaveportion and at least one convex portion, wherein a thickness of themembrane is relatively thicker in the at least one concave portioncompared to the relatively thinner at least one convex portion, and thefirst end of the membrane being configured to collapse inwardly to varya flow path size in response to changes in pressure acting on themembrane, wherein the valve is configured to permit a continuous flow ofgas to be exhausted to atmosphere.
 2. The valve of claim 1, wherein theat least one concave portion and the at least one convex portion aredefined by an inflection on an outer surface of the membrane.
 3. Thevalve of claim 1, wherein the at least one concave portion and the atleast one convex portion are defined by an inflection on an innersurface of the membrane.
 4. The valve of claim 1, wherein the at leastone concave portion and the at least one convex portion are defined byan inflection on at least one of an inner surface and an outer surfaceof the membrane.
 5. The valve of claim 1, wherein the at least oneconcave portion comprises a lobe and the at least one convex portioncomprises a bridging portion.
 6. The valve of claim 5, wherein the valvecomprises only two lobes and only two bridging portions.
 7. The valve ofclaim 5, wherein the valve comprises only three lobes and only threebridging portions.
 8. The valve of claim 5, wherein the valve comprisesonly four lobes and only four bridging portions.
 9. The valve of claim1, wherein the base of the valve is triangular.
 10. The valve of claim1, wherein the base of the valve is circular.
 11. The valve of claim 1further comprising a splint that extends into a mouth defined by thefirst end of the membrane.
 12. The valve of claim 11, wherein the splintextends from the first end of the membrane to the second end of thebase.
 13. A valve assembly comprising the valve of claim 1; and a biasmaterial disposed at the second end of the base.
 14. The valve assemblyof claim 13, wherein the bias material comprises a plurality of biasflow holes.
 15. The valve assembly of claim 13, wherein the biasmaterial comprises a diffuser.
 16. A valve array for use with a systemfor delivering CPAP therapy, the valve array comprising at least twovalves, each of the two valves comprising: a base and a membrane, themembrane having a first end defining an inlet opening disposed into adirection from which flow originates, the base having a second enddefining an outlet opening, the first end of the membrane having atleast one concave portion and at least one convex portion, wherein athickness of the membrane is relatively thicker in the at least oneconcave portion compared to the relatively thinner in the at least oneconvex portion, and the first end of the membrane being configured tocollapse inwardly to vary a flow path size in response to changes inpressure acting on the membrane.
 17. The valve array of claim 16,wherein the at least two valves comprise two rows of valves.
 18. Thevalve array of claim 17, wherein the two rows of valves are nestedtogether.
 19. The valve of claim 1, wherein the flow path size isconfigured to vary between a first size under a first operating pressureand a second size in a second operating pressure higher than the firstoperating pressure, the second size being smaller than the first size.